set +u
  HOSTFILE=$1
set -u
hostlist=$(cat $HOSTFILE | awk '{print $1}' | xargs)
for host in ${hostlist[@]}; do
  echo $host
  ssh -f -n $host "sh -c 'echo \"root               hard    nofile            1024000\" >> /etc/security/limits.conf'"
  ssh -f -n $host "sh -c 'echo \"root               soft    nofile            1024000\" >> /etc/security/limits.conf'"
done
